Convert xml file from one line to multi-lines

Question

I have create a function that convert the input data to xml file; but the result appeared in one line, whereas I want it like this: """

<?xml version="1.0"?>
<pnml xmlns="http://www.pnml.org/version-2009/grammar/pnml">
    <!-- Written by GreatSPN Editor. -->
    <net id="MS" type="http://www.pnml.org/version-2009/grammar/ptnet">
        <name>
            <text>MS</text>
        </name>
        <page id="page0">
            <name>
                <text>DefaultPage</text>
            </name>
            <!-- List of places -->
            <place id="storage">
                <name>
                    <graphics>
                        <offset x="0" y="15"/>
                    </graphics>
                    <text>storage</text>
                </name>

..... """ Please how can I do this in python?